This invention relates to the art of fluid pressure regulating valves, wherein a valve element including a pivotal lever arm is diaphragm actuated to control the flow of fluid through the valve and, more particularly, to the damping of lever arm oscillation during operation of the valve.
It is, of course, well known to provide fluid pressure regulators which operate in accordance with the pressure of fluid acting against a flexible diaphragm which is captured between valve housing components to provide a pressure chamber on one side of the diaphragm and a chamber vented to atmosphere on the other. The pressure chamber includes an inlet orifice for fluid under pressure from a source and an outlet passage for the flow of gas to a point of use such as, for example, a gas-operated cooking grill. A valve element controls the flow of fluid from the inlet orifice to the outlet opening and comprises a lever arm pivotally mounted in the pressure chamber and having an end connected to the diaphragm for the latter to pivot the arm about its axis during operation of the valve. The other end of the lever arm carries a resilient sealing member which, in response to pivotal displacement of the lever arm, engages and disengages the inlet orifice to respectively close and open the latter to the flow of fluid into the pressure chamber from the source. Regulating valves of the foregoing character also include a relief valve arrangement by which excessive back pressure into the pressure chamber from the point of use is vented to atmosphere.
In connection with the operation of such pressure regulating valves heretofore available, when the gas at high input pressure is forced through the restricted orifice into the pressure chamber, the flow velocity of the gas increases at it exits the orifice nozzle into the pressure chamber, whereby the gas rapidly expands and creates high frequency turbulent flow conditions in moving through the pressure chamber to the outlet. The turbulence increases during the regulating mode of operation of the valve because the gas flow is directed radially of the axis of the orifice opening in moving through the pressure chamber to the outlet opening. As a result of the turbulent condition, the lever arm vibrates or oscillates during valve operation causing fluctuating gas flow to the point of use. More importantly, the oscillation can cause diaphragm overtravel and thus, unintended opening of the safety relief valve, resulting in the venting of flammable gas to atmosphere during continued use of the valve and which, in connection with operation of a gas cooking grill, can result in fire and/or explosion.
In accordance with the present invention, a damping arrangement is provided for restraining pivotal displacement of the lever arm so as to eliminate the oscillation thereof and the undesirable flow and operating conditions of the valve resulting therefrom. In accordance with one aspect of the invention, such damping is provided by frictionally restraining pivotal displacement of the lever arm and, in accordance with a preferred embodiment, such frictional restraint is achieved through the mounting of a leaf spring on the lever arm for frictional engagement with a fixed pivot pin for the lever arm.
It is accordingly an outstanding object of the present invention to provide a damping arrangement for the pivotal lever arm of a diaphragm-actuated fluid flow pressure regulating valve.
Another object is to provide a damping arrangement for the operation of a valve element in a diaphragm-actuated pressure regulating valve for minimizing vibration or oscillation of the valve element resulting from turbulent gas flow through the valve.
Yet another object is the provision of a method for controlling the operation of a valve element in a diaphragm-actuated pressure regulating valve for minimizing vibration or oscillation of the valve element resulting from turbulent gas flow through the valve.